The present invention relates to containers for use in cooking products in a microwave oven, and to a composite material for use in fabrication of such containers.
Microwave ovens are becoming a common feature in present day kitchens where their speed and convenience are greatly valued. Accordingly much attention is being paid in the food industry to increasing the types of products which may be cooked in such ovens. A persistent problem, however, has been inability of simple microwave ovens, without special features, to "brown" those products which undergo browning in a conventional oven. This problem arises from the fact that no radiant or convective heat transfer occurs in a simple microwave oven; in fact the food itself absorbs the radiation and heating takes place throughout the food article primarily due to microwave heating of water therein, although some heat transfer by conduction also may take place.
It has been suggested to include in packages for use in microwave ovens one or more metal inserts (susceptors) which absorb microwave radiation--the package material itself must of course be microwave transparent. While such inserts can brown certain areas of a food item, they can become too hot at edges and particularly at corners of packages and the food can become burnt. Various arrangements of the susceptors have been proposed to overcome this problem but these arrangements have proved suitable for certain applications only.
It also is possible to incorporate a browning agent on the surface of the food itself. Such browning agents are well known but have the disadvantage that they can only be used to coat solid food items. A semi-liquid cake batter, for instance, would tend to distribute the browning agent throughout the batter during mixing and the entire cake would be "browned". Such a product would not resemble a conventional oven browned food item and would be less acceptable to the customers.